A 40-year-old man of average height and weight maintains his weight on roughly 2,500 to 3,200 calories a day, depending mostly on how much he moves. Health Canada’s own equation puts a 178 cm (5’10”), 90 kg (198 lb) man at about 2,700 calories if he’s inactive and about 3,100 if he’s active. Treat any formula as a starting estimate, then let two to three weeks of scale readings tell you your real number.
Health Canada’s equation for men 19 and older
Health Canada publishes energy equations for adults that use age, height, weight and one of four activity categories. They come from studies that measured how many calories people actually burned, not from guesswork. For men 19 and older, the Health Canada equations are:
| Activity category | Estimated energy requirement (calories a day) |
|---|---|
| Inactive | 753.07 − (10.83 × age) + (6.50 × height in cm) + (14.10 × weight in kg) |
| Low active | 581.47 − (10.83 × age) + (8.30 × height in cm) + (14.94 × weight in kg) |
| Active | 1,004.82 − (10.83 × age) + (6.52 × height in cm) + (15.91 × weight in kg) |
| Very active | −517.88 − (10.83 × age) + (15.61 × height in cm) + (19.11 × weight in kg) |
Health Canada’s examples help you pick a category. Low active is daily living plus 60 to 80 minutes of walking at 5 to 7 km/h. Active adds roughly 30 to 50 minutes of brisk walking, 45 minutes of moderate cycling and some tennis on top of daily life. Most men with a desk job, a commute and three gym sessions a week sit between inactive and low active, whatever they’d like to believe.
A worked example: a 45-year-old, 178 cm, 90 kg man
Plug in the numbers for the low active category: 581.47 − (10.83 × 45) + (8.30 × 178) + (14.94 × 90) = 581 − 487 + 1,477 + 1,345, which comes to about 2,916 calories a day.
Here is the same man across all four categories, and how the number shifts with age if his size stays put:
| Age | Inactive | Low active | Active | Very active |
|---|---|---|---|---|
| 40 | 2,746 | 2,970 | 3,164 | 3,547 |
| 45 | 2,692 | 2,916 | 3,110 | 3,493 |
| 50 | 2,638 | 2,862 | 3,056 | 3,439 |
| 55 | 2,583 | 2,808 | 3,002 | 3,385 |
Two things stand out. Age matters less than people think: each decade costs about 110 calories. Activity matters a lot: the jump from inactive to active is worth over 400 calories a day, the equivalent of a full meal. Body size matters too. At 110 kg, the same man’s low active estimate rises to about 3,215.
Why Mifflin-St Jeor gives a lower number
The other formula you’ll see in apps is Mifflin-St Jeor, published in 1990. For men it estimates resting energy expenditure, the calories you burn lying still: 10 × weight in kg + 6.25 × height in cm − 5 × age + 5 (Mifflin et al., 1990). For our 45-year-old that gives about 1,792 calories at rest.
Apps then multiply that by an activity factor, typically somewhere between 1.2 and 1.9. Pick a low factor and you’ll get a number hundreds of calories below Health Canada’s estimate. Neither is wrong; they’re built differently. Health Canada’s “inactive” band covers a physical activity level of 1.0 to 1.53 (total burn divided by basal burn), so applying 1.4 to the Mifflin figure (about 2,500) brings the two closer.
The practical lesson: two reputable formulas can disagree by 300 to 500 calories for the same man. That gap is why you calibrate.
How to find your real maintenance number
Your actual intake and the scale will tell you more than any equation. Here’s a two-to-three-week test:
- Pick a starting number. Use the Health Canada estimate for your honest activity category, or run it through the calorie calculator for men over 40.
- Eat close to it every day, weekends included. Log for the full period. Rough tracking still beats none.
- Weigh yourself each morning after the washroom, before food. Write it down.
- Compare weekly averages, not single days. Daily weight swings by a kilo or more with salt, carbs and sleep.
- Adjust. If your weekly average is flat, you’ve found maintenance. If it’s rising about half a kilo a week, you’re roughly 500 over. If it’s falling, you’re under.
Hall and colleagues’ modelling of weight change shows the body adapts slowly to a change in intake, with a half-time of about a year (Hall et al., 2011). That’s another reason to re-check every month or two rather than setting a number once and forgetting it.
What about the “2,000 calories” on Ontario menus?
Under Ontario’s Healthy Menu Choices Act, chains with 20 or more locations must post calories and a statement that adults and youth need an average of 2,000 calories a day (Government of Ontario). That’s a population average across women, men and teenagers. The same Ontario page notes an active man aged 31 to 50 may need about 2,900.
For a man over 40, 2,000 a day is usually a fat-loss intake. That’s useful when you’re reading a menu board: a 1,100-calorie lunch is more than a third of most men’s day, not half of it.
Setting calories for your goal
Once you know maintenance, the goal decides the adjustment:
| Goal | Daily calories | Pair it with |
|---|---|---|
| Lose fat | 300 to 500 below maintenance | Protein at 1.6 g/kg or more, strength training 2 to 4 times a week |
| Recomposition (lose fat, gain some muscle) | 0 to 300 below maintenance | Progressive strength training, high protein |
| Build muscle | About 10% above maintenance | A training program that adds load over time |
The size of a fat-loss deficit deserves its own decision, covered in how big a calorie deficit should be after 40. Whatever the goal, protein comes next: see how much protein a man over 40 needs.
Your next step this week
Calculate your Health Canada estimate tonight, then eat close to it for 14 days and record your morning weight. At the end, you’ll know your maintenance within a couple of hundred calories, which is better than most men ever know. If you’d like someone to set the starting number, review your weigh-ins and adjust it every month as your training and schedule change, that’s what monthly 1:1 coaching is built around.
Questions people also ask
Is 2,000 calories a day enough for a 40-year-old man?
For most men it's a fat-loss intake, not maintenance. The 2,000 figure on Ontario menus is a population average that includes women and teenagers. A 178 cm, 90 kg man who sits most of the day burns closer to 2,700 by Health Canada's equation.
How many calories should a 40-year-old man eat to lose weight?
Start about 300 to 500 below your estimated maintenance and adjust after two to three weeks of weigh-ins. For many men that lands between 2,000 and 2,600 a day. The deficit page explains how to size it.
Do men need fewer calories after 40?
Slightly. Health Canada's equation for men subtracts about 11 calories a day for every year of age, so a man needs roughly 110 fewer calories at 50 than at 40 if nothing else changes. Losing muscle and moving less usually cost more than age itself.
Should I count calories on weekends too?
If you count at all, yes. Your body responds to the weekly total. Two loose days of 1,000 extra calories each can erase most of a 500-a-day weekday deficit.
Sources
- Health Canada — Dietary reference intakes tables: equations to estimate energy requirement
- Mifflin et al. (1990), A new predictive equation for resting energy expenditure in healthy individuals, Am J Clin Nutr
- Government of Ontario — Calories on menus (Healthy Menu Choices Act)
- Hall et al. (2011), Quantification of the effect of energy imbalance on bodyweight, Lancet